Objective: To explore the effect of Agkistrodon acutus venom on angiogenesis in collagen-induced arthritis (CIA) rats. Method: CIA was induced in Lewis rats with bovine type II collagen (1 g·L-1). After induction of CIA for 21 d

rats were randomly divided into six groups:normal group

CIA model group

meloxicam group (0.72 mg·kg-1

ig)

A. acutus venom groups (0.1

0.33

1 mg·kg-1

ip). After treatment once a day for 21 d.The histopathological score was monitored by HE staining in ankle joint synovial tissues

and the microvessel density (MVD) was detected by Von Willebrand factor (vWF) immunostaining. Vascular endothelia growth factor(VEGF) expression and the serum level of angiopoientin 1(Ang-1) were examined by immunohistochemistry and ELISA respectively. Result: Compared with the normal group

histopathological score and MVD significantly increased in CIA model group

as well as the VEGF expression and the serum level of Ang-1 (P<0.01). Compared with CIA model group

histopathological score was significantly decreased by treatment with medium and high dose of A. acutus venom (P<0.05 or P<0.01). Moreover

the MVD

the VEGF expression and the serum level of Ang-1 were significantly reduced by high dose of A. acutus venom( P<0.01). Conclusion: These results suggest that A. acutus venom effectively alleviate the pathological damage and angiogenesis

and its mechanism might be partly related to the decreasing expression of VEGF in ankle joint synovial tissues and the content of Ang-1 in serum.